[0001] The present invention relates to steam ovens.
[0002] Generally, steam ovens are cooking apparatuses that cook food by generating steam
and discharging the steam onto the food.
[0003] Conventional steam ovens include a cabinet to define a cooking cavity therein, a
steam generator to supply steam into the cooking cavity, and a steam feed pipe to
guide and feed the steam generated from the steam generator to a lower portion of
the cooking cavity so as to discharge the steam into the cooking cavity from the lower
portion of the cooking cavity.
[0004] Accordingly, the steam, generated by the steam generator and passing through the
steam feed pipe, is discharged from the lower portion of the cooking cavity to a rack
installed in the cooking cavity, so that food placed on the rack is cooked by heat
of the steam discharged into the cooking cavity.
[0005] In the case that a plurality of racks are sequentially provided in a multi-rack arrangement
in the cooking cavity, because the steam discharged from the lower portion of the
cooking cavity is mainly discharged to a rack provided at a lower portion in the cooking
cavity, the conventional steam ovens may not evenly cook foods that are placed on
the upper and lower racks provided at upper and lower portions in the cooking cavity.
[0006] According to the present invention there is provided an apparatus and method as set
forth in the appended claims. Preferred features of the invention will be apparent
from the dependent claims, and the description which follows.
[0007] Accordingly, the present invention provides a steam oven which selectively heats
food in desired directions.
[0008] The present invention provides a steam oven which evenly cooks foods placed on upper
and lower racks provided at upper and lower portions in the cooking cavity.
[0009] Additional aspects and/or advantages of the invention will be set forth in part in
the description which follows and, in part, will be obvious from the description,
or may be learned by practice of the invention.
[0010] In one aspect of the invention, there is provided a steam oven, having a cabinet
to define a cooking cavity therein, a steam generator to generate overheated steam,
and a plurality of steam feed pipes to guide and supply the overheated steam generated
by the steam generator into the cooking cavity, including outlet ends placed at a
plurality of predetermined positions in the cooking cavity so as to evenly distribute
the overheated steam into the cooking cavity.
[0011] The steam oven may further include a plurality of steam valves mounted at predetermined
portions of the plurality of steam feed pipes. The plurality of steam valves independently
control the plurality of steam feed pipes so as to change positions from which the
overheated steam is discharged into the cooking cavity.
[0012] The plurality of steam feed pipes may include an upper steam feed pipe, including
an outlet end placed at a predetermined portion of an upper wall of the cooking cavity
to discharge the overheated steam from the steam generator into the cooking cavity
in a downward direction, a lower steam feed pipe, including an outlet end placed at
a predetermined portion of a lower wall of the cooking cavity to discharge the overheated
steam from the steam generator into the cooking cavity in an upward direction, and
a side steam feed pipe, including an outlet end placed at a predetermined portion
of a sidewall of the cooking cavity to discharge the overheated steam from the steam
generator into the cooking cavity in a sideward direction.
[0013] The cooking cavity may include a plurality of racks provided at upper and lower positions
in the cooking cavity to support foods thereon. The side steam feed pipe may include
a plurality of side steam feed pipes placed at upper and lower portions of the sidewall
of the cooking cavity so as to respectively discharge the overheated steam from the
steam generator into spaces defined between the plurality of racks in the cooking
cavity.
[0014] The steam generator may include a steam generating vessel communicating with the
cooking cavity through the plurality of steam feed pipes, including a predetermined
amount of water contained in the steam generating vessel, and a first heater to generate
steam. The first heater is installed in the steam generating vessel and immersed in
the water contained in the steam generating vessel. The steam generator may further
include a second heater to generate the overheated steam by further heating the steam
generated by the first heater.
[0015] According to another aspect of the invention there is provided a steam oven having
a cabinet to define a cooking cavity therein, a steam generator to generate steam,
a plurality of steam feed pipes to guide and supply the steam generated by the steam
generator into the cooking cavity, including outlet ends placed at a plurality of
predetermined positions in the cooking cavity so as to evenly distribute the steam
into the cooking cavity, and a plurality of steam valves respectively mounted at predetermined
portions of the plurality of steam feed pipes. The plurality of steam valves independently
controlling the plurality of steam feed pipes so as to change positions from which
the steam is discharged into the cooking cavity.
[0016] The plurality of steam feed pipes may include an upper steam feed pipe, including
an outlet end placed at a predetermined portion of an upper wall of the cooking cavity
to discharge the steam from the steam generator into the cooking cavity in a downward
direction, a lower steam feed pipe, of which an outlet end is placed at a predetermined
portion of a lower wall of the cooking cavity to discharge the steam from the steam
generator into the cooking cavity in an upward direction, and a side steam feed pipe,
including an outlet end placed at a predetermined portion of a sidewall of the cooking
cavity to discharge the steam from the steam generator into the cooking cavity in
a sideward direction.
[0017] The cooking cavity may include a plurality of racks provided at upper and lower positions
in the cooking cavity to support foods thereon. The side steam feed pipe may include
a plurality of side steam feed pipes placed at upper and lower portions of the sidewall
of the cooking cavity so as to discharge the steam from the steam generator into spaces
defined between the plurality of racks in the cooking cavity.
[0018] The steam generator may include a steam generating vessel to communicate with the
cooking cavity through the plurality of steam feed pipes, including a predetermined
amount of water contained in the steam generating vessel, and a heater to generate
steam. The heater is installed in the steam generating vessel and contacts the water
contained in the steam generating vessel.
[0019] For a better understanding of the invention, and to show how embodiments of the same
may be carried into effect, reference will now be made, by way of example, to the
accompanying diagrammatic drawings in which:
FIG. 1 is a front perspective view of a steam oven, according to a first embodiment
of the present invention;
FIG. 2 is a side sectional view showing an internal construction of the steam oven
of FIG. 1; and
FIG. 3 is a side sectional view showing an internal construction of a steam oven,
according to a second embodiment of the present invention.
[0020] Reference will now be made in detail to the embodiments of the present invention,
examples of which are illustrated in the accompanying drawings, wherein like reference
numerals refer to like elements throughout. The embodiments are described below to
explain the present invention by referring to the figures.
[0021] As shown in FIGS. 1 and 2, a steam oven according to a first embodiment of the present
invention includes a cabinet 10 which forms an outer appearance of the steam oven
and defines a cooking cavity 12a therein, and a steam generator 20 which generates
overheated steam so as to supply the overheated steam into the cooking cavity 12a.
[0022] The cabinet 10 includes an outer casing 11 and an inner casing 12. The inner casing
12 is installed in the outer casing 11 spaced apart from the outer casing 11, and
defines the cooking cavity 12a therein. A control unit 13, includes a display 13a
to display an operational state of the steam oven thereon, various kinds of control
buttons 13b, and control switches 13c, provided at an upper portion of the cabinet
10.
[0023] The outer casing 11 and the inner casing 12 are respectively open at a front thereof
so as to allow a user to place and remove foods into and from the cooking cavity 12a.
A door 14, having a lower end attached to a lower portion of the cabinet 10 by hinges,
is provided at the open front of the cooking cavity 12a. The door 14 is opened downward
and closed upward so as to open and close the cooking cavity 12a.
[0024] A rack 15 is provided in the cooking cavity 12a to support food thereon. The rack
15 is removably installed in the cooking cavity 12a to slide along two guide rails
12b which are oppositely formed on inner surfaces of both sidewalls of the inner casing
12 to support the rack 15. In the embodiment of the present invention, a plurality
of racks 15 and a plurality of guide rails 12b may be placed at upper and lower positions
in the cooking cavity 12a so as to support several items of foods on the racks 15
and effectively cook the foods during a cooking operation. In the first embodiment
of the present invention, the upper and lower guide rails 12b are respectively formed
at upper and lower positions on the inner surfaces of both sidewalls of the inner
casing 12, so that upper and lower racks 15 are respectively installed at the upper
and lower positions in the cooking cavity 12a forming a two-rack arrangement. Furthermore,
a temperature sensor (not shown) is installed in the cooking cavity 12a so as to monitor
a temperature of the cooking cavity 12a.
[0025] In the meantime, as shown in FIG. 2, the steam generator 20 includes a steam generating
vessel 21 containing a predetermined amount of water. The steam generating vessel
21 includes a first heater 22 mounted to a lower portion in the steam generating vessel
21 to boil the water, thus generating steam, and a second heater 23 mounted to an
upper portion in the steam generating vessel 21 to further heat the steam generated
by the first heater 22, thus producing overheated steam. Accordingly, the water contained
in the steam generating vessel 21 is boiled to generate the steam by the first heater
22, and the steam rises to the upper portion in the steam generating vessel 21. Sequentially,
the steam is overheated by the second heater 23 mounted at the upper portion of the
steam generating vessel 21 further heating the steam.
[0026] Furthermore, in the steam oven of the present invention, a plurality of steam feed
pipes 30U, 30L, and 30S are arranged around the cooking cavity 12a so as to guide
and supply the overheated steam generated by the steam generator 20 into the cooking
cavity 12a.
[0027] The steam feed pipes 30U, 30L, and 30S are connected to the steam generator 20 at
inlet ends thereof, and are connected to the cooking cavity 12a at outlet ends thereof
so as to feed the overheated steam from the steam generator 20 into the cooking cavity
12a. The outlet ends of the steam feed pipes 30U, 30L, and 30S are respectively placed
at a plurality of predetermined positions of upper, lower and sidewalls of the cooking
cavity 12a, so that the overheated steam is discharged into the cooking cavity 12a
in desired directions to selectively heat desired parts of the food placed in the
cooking cavity 12a.
[0028] That is, in the first embodiment of the present invention, the steam feed pipes comprise
four steam feed pipes 30U, 30L, and 30S (two of them) of which the outlet ends are
respectively placed at predetermined positions of the upper wall, lower wall, and
both sidewalls of the cooking cavity 12a so as to discharge the overheated steam into
the cooking cavity 12a in a downward, upward, and sideward direction.
[0029] The four steam feed pipes 30U, 30L, and 30S (two of them) includes an upper steam
feed pipe 30U, having an outlet end placed at a predetermined portion of the upper
wall of the cooking cavity 12a to discharge the overheated steam into the cooking
cavity 12a in a downward direction, a lower steam feed pipe 30L, having an outlet
end placed at a predetermined portion of the lower wall of the cooking cavity 12a
to discharge the overheated steam into the cooking cavity 12a in an upward direction,
and two side steam feed pipes 30S, having outlet ends placed at predetermined portions
of both sidewalls of the cooking cavity 12a to discharge the overheated steam into
the cooking cavity 12a in a sideward direction.
[0030] Furthermore, a plurality of steam valves 31U, 31L, and 31S (two of them) are respectively
mounted at predetermined portions of the steam feed pipes 30U, 30L, and 30S (two of
them) so as to control the steam feed pipes 30U, 30L, and 30S (two of them). Due to
the above-mentioned construction, the overheated steam is discharged into the cooking
cavity 12a from only desired positions of the upper, lower and sidewalls of the cooking
cavity 12a by operating the steam valves 31U, 31L, and 31S (two of them) which respectively
control the steam feed pipes 30U, 30L, and 30S (two of them) respectively placed at
upper, lower, and side portions of the cooking cavity 12a.
[0031] Accordingly, the steam oven of the present invention heats the food in desired directions
within the cooking cavity 12a.
[0032] That is, when only the upper steam pipe 30U is open by controlling the plurality
of steam valves 31U, 31L, and 31S (two of them), the food is slightly roasted with
the overheated steam directly discharged from the upper steam pipe 30U onto the food.
When only the lower steam pipe 30L is open by controlling the steam valves 31U, 31L,
and 31S (two of them), heat of the overheated steam is transferred to the foods via
the racks 15 and, simultaneously, the overheated steam is distributed within the cooking
cavity 12a after the overheated steam contacts a lower surface of the lower rack 15.
Therefore, the food is evenly cooked with a lower part of the food being initially
cooked and an upper part being cooked last by the overheated steam which is evenly
distributed in the cooking cavity 12a, thus evenly increasing a temperature in the
cooking cavity 12a.
[0033] In the first embodiment of the present invention, the upper and lower racks 15 are
placed at the upper and lower positions in the cooking cavity 12a. The side steam
feed pipes 30S, having the outlet ends aligned with a space between the upper and
lower racks 15, are respectively placed at both sidewalls of the cooking cavity 12a
so as to discharge the overheated steam into the space defined between the upper and
lower racks 15 in the cooking cavity 12a. However, without being limited to the first
embodiment of the present invention, three or more racks 15 may be placed in the cooking
cavity 12a, as shown in FIG. 3 which shows a second embodiment of the present invention.
In the second embodiment, a plurality of side steam feed pipes 30S are placed at the
both sidewalls of the cooking cavity 12a, such that the outlet ends of the plurality
of side steam feed pipes 30S are respectively aligned with spaces defined between
the three or more racks 15. The overheated steam is thus discharged into spaces defined
between the three or more racks 15 in the cooking cavity 12a.
[0034] In the embodiments of the present invention, the steam oven which cooks the food
using the overheated steam is described. Without being limited to the embodiments
of the present invention, the construction of the steam oven of the present invention
may be applied to cooking apparatuses to cook foods using steam.
[0035] Next, the operation and effect of the steam oven of the present invention will be
described herein bellow. For example, in case of cooking a chicken using the steam
oven of the present invention, the temperature in the cooking cavity 12a must increase
to a high level to evenly cook the chicken in the cooking cavity 12a. Therefore, all
the steam feed pipes 30U, 30L, and 30S are open so as to increase the temperature
in the cooking cavity 12a by discharging the overheated steam from all the steam feed
pipes 30U, 30L, and 30S into the cooking cavity 12a.
[0036] When the temperature sensor in the cooking cavity 12a detects the temperature in
the cooking cavity 12a equal to or higher than a preset temperature, the upper steam
feed pipe 30U and the side steam feed pipes 30S are respectively closed by the upper
steam valve 31U and the side steam valves 31S, and only the lower steam feed pipe
30L discharges the overheated steam into the cooking cavity 12a.
[0037] Because the overheated steam, discharged from the lower steam feed pipe 30L into
the cooking cavity 12a, forcefully contacts the lower surface of the lower rack 15,
and is distributed within the cooking cavity 12a, the lower rack 15 is heated and,
simultaneously, the temperature in the cooking cavity 12a increases. Therefore, the
chicken placed in the cooking cavity 12a is evenly cooked with a lower part of the
chicken being cooked initially and an upper part being cooked last.
[0038] Thereafter, to evenly finish cooking the chicken, only the upper steam feed pipe
30U is open while the side steam feed pipes 30S and the lower steam feed pipe 30L
are closed. Accordingly, the overheated steam, which is discharged from the upper
steam feed pipe 30U into the cooking cavity 12a, is directly discharged onto the chicken,
slightly roasting the skin of the chicken, and finishing the cooking operation.
[0039] Furthermore, when the upper and lower racks 15 that support foods thereon are placed
in the cooking cavity 12a in the multi-rack arrangement, the overheated steam, discharged
from the upper and lower steam feed pipes 30U and 30L, may not be fed sufficiently
into the spaces defined between the racks 15. However, in the above state, the foods
in the racks 15 are evenly heated at all areas in the cooking cavity 12a by the overheated
steam discharged from the side steam feed pipes 30S, aligned with the spaces defined
between the racks 15.
[0040] As is apparent from the above description, because a steam oven of the present invention
selectively heats food in desired directions by changing positions from which overheated
steam is discharged into a cooking cavity, various kinds of foods are effectively
cooked.
[0041] Also, in the steam oven of the present invention, even though a plurality of racks
are placed in a multi-rack arrangement, foods supported on the racks 15 are evenly
cooked regardless of positions at which the foods are placed, because the overheated
steam is discharged into the cooking cavity at both sides as well as at a top and
bottom.
[0042] Although a few embodiments of the present invention have been shown and described,
it would be appreciated by those skilled in the art that changes may be made in these
embodiments without departing from the principles and spirit of the invention, the
scope of which is defined in the claims and their equivalents.
[0043] Although a few preferred embodiments have been shown and described, it will be appreciated
by those skilled in the art that various changes and modifications might be made without
departing from the scope of the invention, as defined in the appended claims.
[0044] Attention is directed to all papers and documents which are filed concurrently with
or previous to this specification in connection with this application and which are
open to public inspection with this specification, and the contents of all such papers
and documents are incorporated herein by reference.
[0045] All of the features disclosed in this specification (including any accompanying claims,
abstract and drawings), and/or all of the steps of any method or process so disclosed,
may be combined in any combination, except combinations where at least some of such
features and/or steps are mutually exclusive.
[0046] Each feature disclosed in this specification (including any accompanying claims,
abstract and drawings) may be replaced by alternative features serving the same, equivalent
or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated
otherwise, each feature disclosed is one example only of a generic series of equivalent
or similar features.
[0047] The invention is not restricted to the details of the foregoing embodiment(s). The
invention extends to any novel one, or any novel combination, of the features disclosed
in this specification (including any accompanying claims, abstract and drawings),
or to any novel one, or any novel combination, of the steps of any method or process
so disclosed.
1. A steam oven, comprising:
a cabinet (10) to define a cooking cavity (12a) therein;
a steam generator (20) to generate overheated steam; and
a plurality of steam feed pipes (30U,30L,30S) to guide and supply the overheated steam
generated by the steam generator (20) into the cooking cavity (12a), including outlet
ends placed at a plurality of predetermined positions in the cooking cavity (12a)
so as to evenly distribute the overheated steam into the cooking cavity (12a).
2. The steam oven according to claim 1, further comprising:
a plurality of steam valves (31U, 31L,31S) mounted at predetermined portions of the
plurality of steam feed pipes (30U,30L,30S), the plurality of steam valves (31U,31L,31S)
independently controlling the plurality of steam feed pipes (30U,30L,30S) so as to
change positions from which the overheated steam is discharged into the cooking cavity
(12a).
3. The steam oven according to claim 1 or claim 2, wherein the plurality of steam feed
pipes (30U,30L,30S) comprise:
an upper steam feed pipe (30U), including an outlet end placed at a predetermined
portion of an upper wall of the cooking cavity (12a) to discharge the overheated steam
from the steam generator (20) into the cooking cavity (12a) in a downward direction;
a lower steam feed pipe (30L), including an outlet end placed at a predetermined portion
of a lower wall of the cooking cavity (12a) to discharge the overheated steam from
the steam generator (20) into the cooking cavity (12a) in an upward direction; and
a side steam feed pipe (30S), including an outlet end placed at a predetermined portion
of a sidewall of the cooking cavity (12a) to discharge the overheated steam from the
steam generator (20) into the cooking cavity (12a) in a sideward direction.
4. The steam oven according to claim 3, wherein:
the cooking cavity (12a) comprises a plurality of racks (15) provided at upper and
lower positions in the cooking cavity (12a) respectively to support foods thereon;
and
the side steam feed pipe (30S) comprises a plurality of side steam feed pipes (30S)
placed at upper and lower portions of the sidewall of the cooking cavity (12a) so
as to discharge the overheated steam from the steam generator (20) into spaces defined
between the plurality of racks (15) in the cooking cavity (12a).
5. The steam oven according to any preceding claim, wherein the steam generator (20)
comprises:
a steam generating vessel (21) communicating with the cooking cavity (12a) through
the plurality of steam feed pipes (30U,30L,30S), containing a predetermined amount
of water;
a first heater (22) to generate steam, the first heater (22) installed in the steam
generating vessel (21) and contacting the water contained in the steam generating
vessel (21); and
a second heater (23) to generate the overheated steam by further heating the steam
generated by the first heater (22).
6. A steam oven comprising:
a cabinet (10) to define a cooking cavity (12a) therein;
a steam generator (20) to generate steam;
a plurality of steam feed pipes (30U,30L,30S) to guide and supply the steam generated
by the steam generator (20) into the cooking cavity (12a), including outlet ends placed
at a plurality of predetermined positions in the cooking cavity (12a) so as to evenly
distribute the steam into the cooking cavity (12a); and
a plurality of steam valves (31U,31L,31S) mounted at predetermined portions of the
plurality of steam feed pipes (30U,30L,30S), the plurality of steam valves (31U,31L,31S)
independently controlling the plurality of steam feed pipes (30U,30L,30S) so as to
change positions from which the steam is discharged into the cooking cavity (12a).
7. The steam oven according to claim 6, wherein the plurality of steam feed pipes (30U,30L,30S)
comprise:
an upper steam feed pipe (30U), including an outlet end placed at a predetermined
portion of an upper wall of the cooking cavity (12a) to discharge the steam from the
steam generator (20) into the cooking cavity (12a) in a downward direction;
a lower steam feed pipe (30L), including an outlet end placed at a predetermined portion
of a lower wall of the cooking cavity (12a) to discharge the steam from the steam
generator (20) into the cooking cavity (12a) in a upward direction; and
a side steam feed pipe (30S), including an outlet end placed at a predetermined portion
of a sidewall of the cooking cavity (12a) to discharge the steam from the steam generator
(20) into the cooking cavity (12a) in a sideward direction.
8. The steam oven according to claim 7, wherein:
the cooking cavity (12a) comprises a plurality of racks (15) provided at upper and
lower positions in the cooking cavity (12a) to support foods thereon; and
the side steam feed pipe (30S) comprises a plurality of side steam feed pipes (30S)
placed at upper and lower portions of the sidewall of the cooking cavity (12a) so
as to discharge the steam from the steam generator (20) into spaces defined between
the plurality of racks (15) in the cooking cavity (12a).
9. The steam oven according to any one of claims 6 to 8, wherein the steam generator
(20) comprises:
a steam generating vessel (21) communicating with the cooking cavity (12a) through
the plurality of steam feed pipes (30U,30L,30S), containing a predetermined amount
of water; and
a heater (22) to generate steam, the heater (22) installed in the steam generating
vessel (21) contacting the water contained in the steam generating vessel (21).
10. A steam oven having a cooking cavity (12a), comprising:
a plurality of steam feed pipes (30U,30L,30S) guiding and supplying steam generated
by a steam generator (20) into the cooking cavity (12a), wherein the plurality of
steam feed pipes (30U,30L,30S) include outlet ends placed at a plurality of predetermined
positions in the cooking cavity (12a) so as to evenly distribute the steam into the
cooking cavity; and
a plurality of steam valves (31U,31L,31S) mounted at predetermined portions on the
plurality of steam feed pipes (30U,30L,30S), the plurality of steam valves (31U,31L,31S)
independently controlling the plurality of steam feed pipes (30U,30L,30S) so as to
change positions from which the steam is discharged into the cooking cavity (12a).
11. The steam oven according to claim 10, wherein the plurality of steam feed pipes (30U,30L,30S)
comprise:
an upper steam feed pipe (30U), including an outlet end placed at a predetermined
portion of an upper wall of the cooking cavity (12a) discharging the overheated steam
into an upper section of the cooking cavity (12a);
a lower steam feed pipe (30L), including outlet end placed at a predetermined portion
of a lower wall of the cooking cavity (12a) discharging the overheated steam into
a lower section of the cooking cavity (12a); and
a side steam feed pipe (30S), including an outlet end placed at a predetermined portion
of a sidewall of the cooking cavity (12a) discharging the overheated steam into a
mid-section of the cooking cavity (12a).
12. The steam oven according to claim 11, wherein:
the cooking cavity (12a) comprises a plurality of racks (15) provided at upper and
lower positions in the cooking cavity (12a) supporting foods thereon; and
the side steam feed pipe (30S) further comprising a plurality of side steam feed pipes
(30S) placed at upper and lower portions of the sidewall of the cooking cavity (12a)
so as to discharge the overheated steam into defined spaces between the plurality
of racks (15) in the cooking cavity (12a).
13. The steam oven according to claim 12, wherein outlet ends of the plurality of side
steam feed pipes (30S) are respectively aligned with spaces defined between the plurality
of racks (15).
14. The steam oven according to any one of claims 10 to 13, wherein the steam generator
(20) comprises:
a steam generating vessel (21) communicating with the cooking cavity (12a) through
the plurality of steam feed pipes (30U,30L,30S), containing a predetermined amount
of water;
a first heater (22) generating steam, the first heater (22) installed in the steam
generating vessel (21) and contacting the water; and
a second heater (23) generating the overheated steam by further heating the steam
generated by the first heater (22).
15. A method of operating a steam oven, comprising:
opening a plurality of steam feed pipes (30U,30L,30S) to increase a temperature of
a cooking cavity (12a) by discharging overheated steam from the steam feed pipes (30U,30L,30S)
into the cooking cavity (12a) and
determining the temperature of the cooking cavity (12a);
closing upper and side steam feed pipes (30U, 30S) and selectively discharging the
overheated steam into the cooking cavity through a lower steam feed pipe (30L), if
the temperature of the cooking cavity (12a) is equal to or higher than a preset temperature;
and
selectively opening the upper steam feed pipe (30U) and closing the lower steam feed
pipe (30L), discharging the overheated steam into the cooking cavity (12a) through
the upper steam feed pipe (30U), if the temperature of the cooking cavity (12a) is
less than a preset temperature.